Method and device for replacing rungs on a ladder



May 2, 1961 H. HOPFELD 2,982,373

METHOD AND DEVICE FOR REPLACING RUNGS ON A LADDER Filed Nov. 17, 1958 a9 2 22 l9 l9 INVENTOR. HENRY HOPFELD ATTORNEY.

U ited States Patent METHOD AND DEVICE FOR REPLAING RUNGS ON A LADDERThiszinvention pertains to method and device for replacing rungs on'aladder. l

The primary object of the invention is to provide a method and devicewhereby a broken rung on a ladder can be replaced so that thereplacement rung is integrally united with the rails of. the ladderwithout the necessity of dismantling or disassembling the ladder.

Particularly-it iscan object of the invention to provide a methodanddevice whereby a rung can be extended into the sockets of the oldrung in the rail so as to be suitably cemented therein or integrallyunited by the same type of fiberglass plastic from which the rails aremade.

I am "aware that some changes may be made in the general arrangementsand combinations of the several devices and parts, as well as in thedetails of the construction thereof without departing from the scope ofthe present invention as set forth in the following specification, andas defined in the following claim; hence I do not limit my invention tothe exact arrangements and combinations of the said device and parts asdescribed in the said specification, nor do I confine myself to theexact details of the construction of the said parts as illustrated inthe ac- Fig.2 is a sectional view of said ladder, the section beingItaken on lines Z-Z of Fig. l.

. Fig. 3 -is a fragmental sectional view showing the socket in theladder bored and the end of the replacement rung in position adjacent tothe socket.

Fig. 4 is a fragmental perspective view of the ladder and of theadjacent end of the replacement rung.

Fig. is a developmentview of the fastening elements in the end ofthe'replacement rung.

Fig. 6 is a partly sectional view showing the assembly of thereplacement rung and the installing structure in position, and; p l

Fig. 7 isa fragmental, sectional view of the replacement rung secured inposition.

The type of ladder on which my method and device could be mosteffectively utilized is illustrated herein as a ladder the rails ofwhich are made in part or wholly out of fiberglass. In thepresentillustration the rails are made of an outer fiberglass channel 1and an inner fiberglass channel 2. The inner channel 2 fits into theouter channel 1 andthe channels 1 and Z are integrally united together.At spaced points or locations, where the rungs 3 are placed, areprovided rail sockets 4 for receiving the reduced ends 5 of the rungs 3'as shown in Fig. 1. These rail sockets 4 are formed in this illustrationin wooden blocks 6 which are fillers in the hollow or cavity inside ofthe united opposite channels 1 and 1.

When a rung 3* breaks, then it is removed. In my method the socket 4 isreamed or bored so as to re- 2,982,373 i atented May 2, 1961 move fromthe same the remains of the reduced end 5 of the broken rung 3 and forma clear rail socket.

'A replacement rung 7 is produced with cylindrical sockets 8 in theopposite ends thereof. In each end socket 8 is driven an end plug 9.Each plug 9 is formedwith a reducedouter end 11 which fits into the railsockets 4. The plug 9 is driven into the end socket 8 of the replacementrung.7 so that the reduced end 11 of the plug 9 is concealed within, theend socket 8 and the outer end thereof is flush with the-end of thereplacement rung 7. In the reduced end 11 of the plug 9 is an axialthreaded hole 12 into which fits a pull screw 13. 1

After the opposite rail sockets -4 are rebored, or cleared, thereplacement rung 7 with the plugs 9* inside each end is placed inregistry with the rebored rail sockets 4. A central hole 14 is drilledthrough the outer channel 1 into the center of the bottom 16 of eachrail socket 4 through which the pull screw 13 is inserted and screwedinto the threaded hole 12 in the reduced end 11 of the plug 9. Then thescrew 13 is turned while its head 17 bears against the outside face 18of the rail either directly or through a bearing plate 19 so as to pullthe tightly fitting plug 9' out of the end socket 8 and to pull itsreduced end 11 into the rail socket 4. The reduced end 11 of each plug9' is of a length generally corresponding to the depth of each railsocket 4 so that the shoulder 21 thereof will be flush with the adjacentend of the replacement rung 7 when the reduced end 11 is completelypulled into the rail socket. 4, and will bear against the adjacent faceof the rail. i

As a preliminary step, the cleared rail socket 4 is filled with suitableplastic cement such as a cold setting plastic,

pands during the insertion ofjthe reduced end in the socket and duringsetting, so as to positively integrate the plug with the cylindrical endsocket of the replacement rung as well as the reduced end with the railsocket.

Thebearing plate 19 protects the outer face of the rail around thedrilled hole. After the replacement rung is in place the bearing platesand the pull screws are removed and the remaining cavity is filled withthe same plastic cement, and the plastic cement sets in the rail socketand around the reduced ends and in the ends of the rung and thereby afirm integrated connection is achieved between the new rung and the railof the ladder.

I claim:

1. The method of replacing a rung in the rails of a ladder comprising,forming sockets in the rails for the opposite ends of the rung, tightlydriving into each end of the rung a plug longer than the depth of theadjacent rail socket, filling the rail sockets with plastic cementcapable of integrating the plugs with the rail sockets, placing the rungin the leadder with the ends of the rung in registry with the respectivesockets, and partly withdraw ing said plugs axially from said rung andinto the respective rail sockets for integration with said rail sockets.

2. The method of replacing a rung in the rails of a ladder comprising,forming opposite sockets in the rails, completely concealing in each endof a rung a plug formed so that said rung fits between the rails of theladder when the outer end of the plug is in registry with the adjacentsocket, filling the sockets with plastic cement capable of integratingthe outer ends of the plugs with the respective sockets, placing saidrung in said ladder in registry with said opposite sockets, and partlywithdrawing said plugs axially from said rung and into the respectivesockets so as to force part of said plastic cement into the ends of saidrung and around said plugs for integrating said plugs with said socketsand with the ends of said rung.

3. The method of replacing a rung in opposite rails of a laddercomprising, forming opposite sockets in said rails, forming a rung withplugs in its opposite ends with passage for plastic cement about eachplug, driving each plug into the adjacent end of the rung so as tocompletely conceal the plug, filling each socket with plastic cementcapable of integrating each plug with the adjacent socket and with saidrung, placing said rung between the opposite rails of said ladder inregistry with said sockets and partly withdrawing each plug axially fromthe rung and into the adjacent socket so as to force part of saidplastic cement into said passage about said plug for integrating saidplugs with the respective sockets and with said rung.

4. The method of replacing a rung in opposite rails of a ladder,comprising forming sockets in the rail, driving into each end of therung a plug so that the ends of the plugs are flush with the respectiveends of the rung, forming an access hole in the bottom of each socket,aligning the rung with said sockets, filling said sockets with a plasticcement capable of integrating the plugs with the sockets, engaging saidplugs through the respective access holes and drawing the plugs into therespective sockets so that a portion of each plug remains in the rungand part of said plastic cement.is forced around each plug into therung, and allowing said plastic cement to set.

5. A replacement rung for a ladder having rail sockets in the railsthereof comprising a rung body having a cavity in each end thereof, aplug tightly fitting and concealed within each cavity, the outer portionof each plug fitting into the adjacent socket when pulled thereinto, andcement receiving means at the peripheries of said plugs for receivingplastic cement forced from said sockets along the plug peripheries forintegrating said plugs with said rail sockets and with said rung in saidcavity.

6. A replacement rung for the rails of a ladder having opposite railsockets, comprising a generally cylindrical rung, a rung socket in eachend of the rung, a plug forced completely into said rung socket so thatthe outer end of the plug is substantially flush with the adjacent endof the rung, said rung being of a length substantially equal to thedistance between said rails, engagement means in the end of each plugfor pulling the plug adapted to be engaged and axially pulled into aadjacent rail socket in said rails for integrating with said rails.

7. A replacement rung for the rails of a ladder having opposite railsockets, comprising a generally cylindrical rung, a rung socket in eachend of the rung, a plug forced completely into said rung socket so thatthe outer end of the plug is substantially flush with the adjacent endof the rung, said rung being of a length substantially equal to thedistance between said rails, engagement means in the end of each plugfor pulling the plug adapted to be engaged and axially pulled into anadjacent rail socket in said rails for integrating with said rails, saidend of said plug being reduced and said reduced end being substantiallythe same length as the depth of the rail socket.

8. A replacement rung for the rails of a ladder having opposite railsockets, comprising a generally cylindrical rung, a rung socket in eachend of the rung, a plug forced completely into said rung socket so thatthe outer end of the plug is substantially flush with the adjacent endof the rung, said rung being of a length substantially equal to thedistance between said rails, engagement means in the end of each plugfor pulling the plug adapted to be engaged and axially pulled into anadjacent rail socket in said rails for integrating with said rails, saidend of said plug being reduced and said reduced end being substantiallythe same length as the depth of the railsocket, and said reduced end andsaid plug having grooves on the outer peripheries thereof for receivingcementing material for uniting said plug respectively with said railsocket and with said socket in said replacement rung.

9. A replacement rung for the rails of a ladder having opposite railsockets for rungs, comprising a generally cylindrical rung, a rungsocket in each end .of the rung, a plug forced completely into said rungsocket so that the outer end of the plug is substantially flush with theadjacent end of the rung, said rung being of a length substantiallyequal to the distance between said rails, a threaded hole in the end ofeach plug adapted to be engaged for pulling the plug axially into anadjacent rail socket in said rails for integrating with said rails, anda pull member engageable with said threaded hole through said adjacentrail socket and with said rail for pulling said plug into the adjacentrail.

10. A replacement rung of the rails of a ladder having opposite railsockets for rungs, comprising a generally cylindrical rung, a rungsocket in each end of the rung, a plug forced completely into said rungsocket so that the outer end of the plug is substantially flush with theadjacent end of the rung, said rung being of a length substantiallyequal to the distance between said rails, a threaded hole in the end ofeach plug adapted to be engaged for pulling the plug axially into anadjacent rail socket in said rails for integrating with said rails, anda pull member engageable with said threaded hole through said adjacentrail socket for pulling said plug into the adjacent rail, a head on saidpull-member, and a bearing element between each head and the adjacentrail.

References Cited in the file of this patent UNITED STATES PATENTS925,105 Kaufman June 15, 1909 1,644,694 Rowe Oct. 11, 1927 FOREIGNPATENTS 468,382 Germany Nov. 12, 1928 362,382 Great Britain Dec. 2, 1931100,807 Australia Apr. 14, 1937 940,732 Germany Mar. 22, 1956

